Knock Knock

Everyone is always busy. This is a fact. So what happens when the doorbell rings at the office? We ignore it. The most annoying is when one of our colleagues forgets to bring the damn RFID card!
So, with a little bit of soldering, programming and creativity we turned the activity of knocking into a password protected door-opening system.
Contact microphones were attached on the glass surface of the door and a servo below the RFID reader. When you enter the five-digit code, by knocking on the correct spots on the window, the servo is activated, which moves the card front of the reader. It’s that simple!